[Bug tree-optimization/121104] [14/15 Regression] ICE at O2: verify_gimple_in_cfg(function*, bool, bool)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121104

--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-15 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:79995188168cefe2d2be07cfa3fdde97f28edc54

commit r15-10893-g79995188168cefe2d2be07cfa3fdde97f28edc54
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Feb 2 10:07:15 2026 +0100

    widening_mul: Fix UADDC/USUBC pattern matching [PR121104]

    As the following testcase shows, I've missed a check that element type
    of lhs type of ovf1/ovf2 (.ADD_OVERFLOW/.SUB_OVERFLOW) matches type (there
    are some casts accepted on the way for the case of values in [0-1] range),
    so the following testcase got also matched as .SUBC and we get an ICE on
    type mismatch in there.  The other .{ADD,SUB}_OVERFLOW cases already check
    even the result type, both
                        if (gimple_call_internal_p (ovf, code == PLUS_EXPR
                                                         ? IFN_ADD_OVERFLOW
                                                         : IFN_SUB_OVERFLOW))
    ...
                            ovf_lhs = gimple_call_lhs (ovf);
                            tree ovf_lhs_type = TREE_TYPE (TREE_TYPE
(ovf_lhs));
                            ovf_arg1 = gimple_call_arg (ovf, 0);
                            ovf_arg2 = gimple_call_arg (ovf, 1);
                            /* In that case we need to punt if the types don't
                               mismatch.  */
                            if (!types_compatible_p (type, ovf_lhs_type)
                                || !types_compatible_p (type, TREE_TYPE
(ovf_arg1))
                                || !types_compatible_p (type,
                                                        TREE_TYPE (ovf_arg2)))
                              ovf_lhs = NULL_TREE;
    and
              gimple *ovf3
                = SSA_NAME_DEF_STMT (TREE_OPERAND (gimple_assign_rhs1 (im3),
0));
              if (gimple_call_internal_p (ovf3, ifn))
                {
                  lhs = gimple_call_lhs (ovf3);
                  arg1 = gimple_call_arg (ovf3, 0);
                  arg2 = gimple_call_arg (ovf3, 1);
                  if (types_compatible_p (type, TREE_TYPE (TREE_TYPE (lhs)))
                      && types_compatible_p (type, TREE_TYPE (arg1))
                      && types_compatible_p (type, TREE_TYPE (arg2)))

    2026-02-02  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/121104
            * tree-ssa-math-opts.cc (match_uaddc_usubc): Punt if
            lhs of ovf1 or ovf2 doesn't have element type compatible with type.

            * gcc.dg/pr121104.c: New test.

    (cherry picked from commit 49c7fc2d534cb7e16f0e95fd89f47eb0b0d34762)